Coupled precipitation-ultrafiltration for treatment of high fluoride-content wastewater

Liu, Ching-Chung; Liu, J.C.

doi:10.1016/j.jtice.2015.05.038

Cited by 63 publications

(17 citation statements)

References 20 publications

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“…Recently, great attention has been paid to the treatment of high fluoride water and researchers have conducted various investigations to develop effective ways to remove fluoride from polluted water. The most common treatment methods for fluoride polluted water including chemical precipitation, flocculation precipitation, electro-coagulation, membrane separation, adsorption, and ion exchange [2][3][4][5][6][7][8][9][10][11]. Among them, adsorption is a relatively convenient and cost-effective way that can remove fluoride from polluted water.…”

Section: Introductionmentioning

confidence: 99%

Removal of fluoride from aqueous solution by TiO₂ and TiO₂–SiO₂ nanocomposite

Zeng

Xue

Liang

et al. 2016

Chemical Speciation & Bioavailability

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Adsorption plays an important role in the removal of pollutants such as fluoride from aqueous solutions. With the rapid development of environmental technology, TiO 2 particle has become promising material to adsorb fluoride ion because of its low cost, non-toxic, good chemical stability, and good sorption ability. This work used sol-gel and hydrothermal synthesis methods to prepare TiO 2 particles and load them onto SiO 2 particles. The physicochemical properties such as heat stability, particle size, and surface area of the resulting TiO 2 adsorbents were characterized with various analytical methods. In addition, their adsorption abilities to fluoride were determined under various conditions including different initial fluoride concentration, pH and coexisting ions. The maximum adsorption capacity of the TiO 2 adsorbents can reach up to 94.3 mg/g. The adsorption isotherms of fluoride onto the TiO 2 adsorbents can be closely described by the Langmuir model, suggesting the monolayer adsorption process.

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Section: Introductionmentioning

confidence: 99%

Removal of fluoride from aqueous solution by TiO₂ and TiO₂–SiO₂ nanocomposite

Zeng

Xue

Liang

et al. 2016

Chemical Speciation & Bioavailability

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“…Despite several fluoride removal methods, economic, procedural, and environmental disadvantages restrict their wide usage in many parts of the world. Although reverse osmosis [ 14 , 15 ], ultrafiltration [ 16 ], electrodialysis [ 17 ], and ion exchange [ 18 , 19 , 20 ] have good fluoride removal efficiency and are fairly steady, their operating costs are prohibitively high for developing countries like Ethiopia. The coagulation sedimentation methods [ 21 , 22 , 23 , 24 ] are simple to use, low cost and simple to apply; nevertheless, the dosage is too high and cannot be regenerated, causing secondary pollution and difficulty reducing fluoride to permissible levels.…”

Section: Introductionmentioning

confidence: 99%

Enhanced Defluoridation of Water Using Zirconium—Coated Pumice in Fixed-Bed Adsorption Columns

2021

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Millions of people across the globe suffer from health issues related to high fluoride levels in drinking water. The purpose of this study was to test modified pumice as an adsorbent for the purification of fluoride-containing waters. The adsorption of fluoride onto zirconium-coated pumice (Zr–Pu) adsorbent was examined in fixed-bed adsorption columns. The coating of zirconium on the surface of VPum was revealed by X-ray diffractometer (XRD), Inductively coupled plasma-optical emission spectroscopy (ICP-EOS), and X-ray fluorescence (XRF) techniques. The degree of surface modification with the enhanced porosity of Zr–Pu was evident from the recorded scanning electron microscope (SEM) micrographs. The Brunauer-Emmett-Teller (BET) analysis confirmed the enhancement of the specific surface area of VPum after modification. The Fourier transform infrared (FTIR) examinations of VPum and Zr–Pu before and after adsorption did not reveal any significant spectrum changes. The pH drift method showed that VPum and Zr–Pu have positive charges at pHPZC lower than 7.3 and 6.5, respectively. Zr–Pu yielded a higher adsorption capacity of 225 mg/kg (2.05 times the adsorption capacity of VPum: 110 mg/kg), at pH = 2 and volumetric flow rate (QO) of 1.25 mL/min. Breakthrough time increases with decreasing pH and flow rate. The experimental adsorption data was well-matched by the Thomas and Adams-Bohart models with correlation coefficients (R2) of ≥ 0.980 (Zr–Pu) and ≥ 0.897 (VPum), confirming that both models are suitable tools to design fixed-bed column systems using volcanic rock materials. Overall, coating pumice with zirconium improved the defluoridation capacity of pumice; hence, a Zr–Pu-packed fixed-bed can be applied for defluoridation of excess fluoride from groundwater. However, additional investigations on, for instance, the influences of competing ions are advisable to draw explicit conclusions.

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“…In order to remove F − from water, several conventional treatment methods have been developed, including adsorption, precipitation, electrodialysis, nanofiltration, and reverse osmosis . However, chemical precipitation with lime and calcium salt can produce very fine CaF 2 precipitate, which is difficult to remove and requires polymeric flocculent to separate the precipitate from water . Induced crystallization, which is based on the crystallization of CaF 2 upon seed materials, rather than mass precipitation in the liquid phase, can be used for the removal of F − from wastewater .…”

Section: Introductionmentioning

confidence: 99%

“…[10][11][12][13] However, chemical precipitation with lime and calcium salt can produce very fine CaF 2 precipitate, which is difficult to remove and requires polymeric flocculent to separate the precipitate from water. 14,15 Induced crystallization, which is based on the crystallization of CaF 2 upon seed materials, rather than mass precipitation in the liquid phase, can be used for the removal of F − from wastewater. 16 This process has notable advantages, such as regeneration of the material from waste and reduction in sludge volume, compared with the precipitation process.…”

Section: Introductionmentioning

confidence: 99%

Investigation of fluorapatite crystallization in a fluidized bed reactor for the removal of fluoride from groundwater

Deng

Zhang

Zhou

2018

J of Chemical Tech & Biotech

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BACKGROUND This work further investigates fluoride removal from groundwater by induced crystallization in batch experiments and in a fluidized bed reactor (FBR). Phosphate rock (PR), which is an abundant ore and represents the basic raw material for the phosphatic fertilizer industry, was used as seed crystal in the induced crystallization process. RESULTS Induced crystallization in FBR reduced the concentration of F− in synthetic groundwater from 9.5 mg L‐1 to <1.0 mg L‐1. Phases with the potential for precipitation were calculated through thermodynamic equilibrium modeling. The formed precipitates were identified by powder x‐ray diffraction (XRD) and scanning electron microscopy, coupled with energy dispersive spectroscopy (SEM–EDS). Finally, fluorapatite crystallization mechanisms were confirmed by the induced crystallization of Ca5(PO4)3F on the surface of PR. CONCLUSION The fluorapatite crystallization process in FBR removed F− from groundwater, and the used seed crystal PR was rich in phosphorus and that could be recovered as raw material for the phosphatic fertilizer industry. © 2018 Society of Chemical Industry

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Coupled precipitation-ultrafiltration for treatment of high fluoride-content wastewater

Cited by 63 publications

References 20 publications

Removal of fluoride from aqueous solution by TiO₂ and TiO₂–SiO₂ nanocomposite

Removal of fluoride from aqueous solution by TiO₂ and TiO₂–SiO₂ nanocomposite

Enhanced Defluoridation of Water Using Zirconium—Coated Pumice in Fixed-Bed Adsorption Columns

Investigation of fluorapatite crystallization in a fluidized bed reactor for the removal of fluoride from groundwater

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Coupled precipitation-ultrafiltration for treatment of high fluoride-content wastewater

Cited by 63 publications

References 20 publications

Removal of fluoride from aqueous solution by TiO2 and TiO2–SiO2 nanocomposite

Removal of fluoride from aqueous solution by TiO2 and TiO2–SiO2 nanocomposite

Enhanced Defluoridation of Water Using Zirconium—Coated Pumice in Fixed-Bed Adsorption Columns

Investigation of fluorapatite crystallization in a fluidized bed reactor for the removal of fluoride from groundwater

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Removal of fluoride from aqueous solution by TiO₂ and TiO₂–SiO₂ nanocomposite

Removal of fluoride from aqueous solution by TiO₂ and TiO₂–SiO₂ nanocomposite